Published February 27, 2010, 07:23 PM

Crows predict spring, prompt speculation

Crows are pretty gregarious during the winter, often occurring in quite large flocks. I’ve seen 50 or more at a time in Grand Forks and at leasat half as many along roads in rural Grand Forks County.

By: Mike Jacobs, Grand Forks Herald

A couple of crows showed up Saturday morning at my place west of Gilby, N.D. I count them as signs of spring.

Crows are pretty gregarious during the winter, often occurring in quite large flocks. I’ve seen 50 or more at a time in Grand Forks and at leasat half as many along roads in rural Grand Forks County.

As the light grows stronger, crows grow less sociable. The large flocks characteristic of wintering crows begin to break up into smaller groups.

These are probably family groups, composed of an adult pair and their offspring of the previous year. This is the key grouping in crow culture.

Crows are apparently monogamous. The pair, of course, breed and produce eggs. Associated family members may help with domestic chores, including gathering nesting material and guarding the clan’s territory.

But they don’t help incubate the eggs. The female alone takes on this responsibility. The male does share the work of feeding fledglings.

It may be that yearling birds help raise the brood, which would be full siblings — born of the same parents — but not brood mates. Or yearling birds may be loafers, simply hanging around.

But even this behavior may benefit the crow family because unoccupied birds would be able to spread an alarm about any intruders in the family’s domain.

This may help explain the crow’s extraordinary sensitivity to any disturbance.

My first memory of crows is hunting them with my older brother. He carried the shotgun, and I tagged along. On all of our excursions over many years, he never killed a crow.

That’s how I learned that killing is the lesser part of hunting. Being outdoors, in pursuit of quarry, is the greater part.

Of course, that’s also what birding is about.

Crows are easy birds to see. They’re big, they’re black and they’re noisy.

But they are little-known and still less understood. In fact, they are birds of mystery.

I can’t know for certain that the birds at my place were an adult pair. Courtship simply isn’t a big thing with crows. Unlike many other bird species, including most ducks and many songbirds, there is no nuptial display among crows. Males and females simply hang out together, build a nest together, raise young together and apparently remain together until one or the other of them dies.

Divorce among crows is reportedly rare.

Neither are crows public about their nest-building. On several occasions, I’ve seen crows carrying twigs, and once I imagined that I had discovered where they built a nest.

Here’s another way in which yearlings may help the family, by distracting interested parties — whether birders or predators — from the nest site.

All of this suggests a couple of things about crows.

First, they have a well-organized social system.

Second, groups of crows may function as a disciplined unit and not as individual operatives. Yearlings may have a role as eyes and ears — and even voices — of the unit while breeding adults are occupied with reproduction and nesting.

Similarly, individual crows may serve a kind of journalistic function for the crow community. Ravens, close relatives of crows, are known to communicate with one another about the presence of food, for example.

Crows likely do this, too.

This may help explain why crows form much larger flocks in winter than in summer. Sentinels, or perhaps simply lucky individuals, find food and let other crows know about it.

It’s the same with shelter.

These two elements, food and shelter, make it possible for crows to spend the winter in the Red River Valley. As scavengers, crows find food wherever humans leave garbage, and they find shelter wherever humans plant trees, especially evergreens.

But not all crows are residents. In fact, crows can be long-distance migrants. Birds banded in northern Saskatchewan have been found in Oklahoma. Certainly, some of these birds passed through North Dakota.

So, here is another question about crows: Does the crow population boom in winter because country crows move into the city? Or because Canadian crows — like their human counterparts — find Grand Forks an appealing destination?

Similarly, are the crows in my shelterbelt local crows? Or crows returning from a winter vacation?

It doesn’t really matter. They are welcome as signs of spring.

Jacobs is editor and publisher of the Herald.